Add Driver.useSingleContextManager to turn on single context manager.

pkg/analysis_server/lib/src/socket_server.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library socket.server;
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/channel/channel.dart';
 import 'package:analysis_server/src/plugin/server_plugin.dart';
@@ skipping 19 matching lines @@
   /**
    * The function used to create a new SDK using the default SDK.
    */
   final SdkCreator defaultSdkCreator;
 
   final DirectoryBasedDartSdk defaultSdk;
   final InstrumentationService instrumentationService;
   final ServerPlugin serverPlugin;
   final EmbeddedResolverProvider embeddedResolverProvider;
   final ResolverProvider packageResolverProvider;
+  final bool useSingleContextManager;
 
   /**
    * The analysis server that was created when a client established a
    * connection, or `null` if no such connection has yet been established.
    */
   AnalysisServer analysisServer;
 
   /**
    * The plugins that are defined outside the analysis_server package.
    */
   List<Plugin> userDefinedPlugins;
 
   SocketServer(
       this.analysisServerOptions,
       this.defaultSdkCreator,
       this.defaultSdk,
       this.instrumentationService,
       this.serverPlugin,
+      this.embeddedResolverProvider,
       this.packageResolverProvider,
-      this.embeddedResolverProvider);
+      this.useSingleContextManager);
 
   /**
    * Create an analysis server which will communicate with the client using the
    * given serverChannel.
    */
   void createAnalysisServer(ServerCommunicationChannel serverChannel) {
     if (analysisServer != null) {
       RequestError error = new RequestError(
           RequestErrorCode.SERVER_ALREADY_STARTED, "Server already started");
       serverChannel.sendResponse(new Response('', error: error));
@@ skipping 21 matching lines @@
 
     analysisServer = new AnalysisServer(
         serverChannel,
         resourceProvider,
         new PubPackageMapProvider(resourceProvider, defaultSdk),
         index,
         serverPlugin,
         analysisServerOptions,
         defaultSdkCreator,
         instrumentationService,
+        embeddedResolverProvider: embeddedResolverProvider,
         packageResolverProvider: packageResolverProvider,
-        embeddedResolverProvider: embeddedResolverProvider,
         rethrowExceptions: false);
     analysisServer.userDefinedPlugins = userDefinedPlugins;
   }
 }